Page 1684 - Cote clinical veterinary advisor dogs and cats 4th

846 Pupil Abnormalities

PHYSICAL EXAM FINDINGS consisting of alternating tall-short QRS PROGNOSIS & OUTCOME
• Systemic or primary cardiac problems may complexes, that suggests pericardial effusion Varies widely, depending on underlying cause
VetBooks.ir • Femoral pulses are easiest to palpate in cats DIAGNOSIS PEARLS & CONSIDERATIONS
and is unrelated to pulsus alternans.
alter the pulse, and a complete physical exam
is necessary.
and dogs.
• The dorsal metatarsal pulse is also readily Diagnostic Overview Comments
palpable. A pulse abnormality is a physical exam finding, • Palpation of the peripheral arterial pulse can
• Auscultate heart sounds simultaneously and its significance may vary from harmless give useful information about stroke volume
(by definition, a pulse deficit exists when a (e.g., seemingly weak pulse in an obese patient) and cardiac output.
heart sound does not have a corresponding to indicative of cardiac or systemic disturbances. • Palpation of the arterial pulse is not useful
palpable peripheral pulse). An intermittent pulse deficit should be investi- for detecting systemic hypertension.
• Pulse quality relates mainly to pulse ampli- gated initially with an electrocardiogram; a weak • Presence of a hyperkinetic pulse may be
tude (also affected by rate of rise of arterial pulse should be assessed with evaluation of the more obvious than a diastolic murmur with
pressure in systole and affected by pulse patient’s intravascular volume status (hydration) severe aortic insufficiency (as with infective
duration). and cardiac function (auscultation, thoracic endocarditis of the aortic valve).
radiographs, echocardiogram). • Pulsus paradoxus is a very helpful finding
Etiology and Pathophysiology when cardiac tamponade is suspected, but
• Pulse pressure: difference between systolic Differential Diagnosis it may be difficult to detect if the dog is
and diastolic blood pressure (BP) • Hypokinetic pulse: obesity, arterial disease/ panting.
○ Pulse pressure can be widened by an increase disorder. The combination of hypokinetic
in stroke volume or decreased diastolic BP pulse and a palpably strong or hyperdynamic Technician Tip
(e.g., aortic insufficiency, patent ductus heartbeat (apex beat) strongly suggests Absent metatarsal pulses can be an indication
arteriosus), increasing pulse amplitude. outflow obstruction (e.g., moderate to of hypotension.
• With premature beats, the weak ventricular marked aortic stenosis; less commonly,
contraction may not generate sufficient pulmonic stenosis). SUGGESTED READING
systolic pressure to open the aortic valve, • Hyperkinetic pulse: thin body condition Perloff JK: The arterial pulse. In Perloff JK: Physical
and no S 2 or pulse is produced (S 1 is still • Variation in pulse amplitude: normal examination of the heart and circulation, ed 4,
normally heard). variation as occurs with respiratory sinus Shelton, CT, 2009, People’s Medical Publishing
• Variations in stroke volume also occur with arrhythmia (pulse is stronger after pause) House, pp 55-91.
the phase of respiration with cardiac tampon-
ade, in which increased filling of the right Initial Database RELATED CLIENT EDUCATION
heart during inspiration leads to decreased • Pulse deficits should prompt the recording SHEET
filling of the left heart and a reduced pulse of an electrocardiogram (p. 1096).
pressure. • Alternate pulse deficits with normal sinus Consent to Perform Echocardiography
• Pulsus alternans is an uncommon finding rhythm (pulsus alternans): thoracic radio-
characterized by alternate pulses that are very graphs and an echocardiogram AUTHOR: Virginia Luis Fuentes, VetMB, MA, PhD,
weak or absent despite consistent electrical DVC, DACVIM, DECVIM
EDITOR: Leah A. Cohn, DVM, PhD, DACVIM
activation (due to abnormal intracellular TREATMENT
calcium cycling in myocardial failure).
It should not be confused with electrical Treatment Overview
alternans, an electrocardiographic finding Manage the underlying cause.

Pupil Abnormalities

BASIC INFORMATION GENETICS, BREED PREDISPOSITION HISTORY, CHIEF COMPLAINT
• Distorted pupil: a distorted pupil, such Abnormalities in pupil size and shape may be
Definition as iris coloboma, may be breed related in noted by the owner. Veterinarians may notice
Abnormalities include pupils that are inap- dogs. Australian shepherds and Dalmatians the pupil abnormalities during routine exams
propriately dilated or constricted and those are overrepresented. or in animals presenting for painful, red, or
with a distorted shape. • Dilated pupil blind eyes.
• Anisocoria: unequal or asymmetrical pupils ○ Glaucoma, primary (predisposed breeds)
• Dyscoria: misshapen/distorted pupil ○ Toy and miniature poodles are predisposed PHYSICAL EXAM FINDINGS
• Miosis: constricted pupil to optic nerve hypoplasia. Dilated pupil and the following:
• Mydriasis: dilated pupil ○ Heritable retinal degeneration in many • Scalloping at pupillary margin
breeds of dogs ○ Iris coloboma: focal; young animal
Epidemiology ○ Iris atrophy: typically multifocal and/or
SPECIES, AGE, SEX Clinical Presentation moth-eaten effect in iris stroma and/or
• Dogs and cats DISEASE FORMS/SUBTYPES at pupillary margin; typically age-related
• Iris atrophy is an aging change and is Conditions that lead to pupil abnormalities change (i.e., older animals)
therefore seen in older animals. can be divided into those that cause • Blindness (negative menace response)
• Iris coloboma (absence of or defect in the • Pupillary dilation (mydriasis) ○ See chapters on blindness, retinal degen-
iris) is a developmental/heritable condition • Pupillary constriction (miosis) eration, and retinal detachment (pp. 123,
that is usually first noticed in young animals, • Abnormal pupil shape (dyscoria) 883, and 885).
most frequently dogs.
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